The SW9VE is in the Sigma line, which is the lowest price line.
The SD9VE is the latest version in the SD line, which is mid-level between the Sigma and M&P lines.
While the two share the same grip angle, the SD line allegedly has a better trigger and sights than the Sigmas. The slide also features more elaborate finishing.
There are other differences, I'm sure, that others may elaborate on.